#include<stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include<stdlib.h>

int main()
{
    const char*filename="./record.txt";
    int ret= truncate(filename,100);
    if(ret==-1)
    {
        printf("truncate error:\n");
        exit(-1);
    }



    return 0;
}